compound-types/string #198
giscus
bot
Replies: 38 comments 16 replies
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第10题您要求修改以下代码行，但实际上是要把上面一行的 fn main() {
let raw_str = r"Escapes don't work here: \x3F \u{211D}";
// 修改以下代码行，让它工作
assert_eq!(raw_str, "Escapes don't work here: ? ℝ");
// 如果你希望在字符串中使用双引号，可以使用以下形式
let quotes = r#"And then I said: "There is no escape!""#;
println!("{}", quotes);
// 如果希望在字符串中使用 # 号，可以如下使用：
let delimiter = r###"A string with "# in it. And even "##!"###;
println!("{}", delimiter);
// 填空
let long_delimiter = __;
assert_eq!(long_delimiter, "Hello, \"##\"")
} |
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好的。。。我看看，感谢反馈 |
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看了下，确实是这个问题，非常感谢～ |
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我直接改成了 let raw_str = r"Escapes don't work here: ? ℝ";
assert_eq!(raw_str, "Escapes don't work here: ? ℝ"); |
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我自己是改成： let raw_str = r"Escapes don't work here: \x3F \u{211D}";
// 修改以下代码行，让它工作
assert_eq!(raw_str, "Escapes don't work here: \\x3F \\u{211D");這樣應該比較符合原本題目意思 |
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Done. |
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https://github.com/sunface/rust-by-practice/blob/master/solutions/collections/String.md |
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let s: Box<&str> = "hello, world".into();
当前面 当 在这个例子中，我个人理解的是：栈上保留的智能指针，指向的是 |
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"hello, world".into() 这三种转换方式有什么区别吗？还有其他转换方式吗 |
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和deRef解引用和隐式自动解引用 有关。 |
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稍微看了下源码， to_string()方法的源码实现就是③， into()是 |
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let s: Box<&str> = "hello, world".into(); 这一行代码的作用是将字符串字面量"hello, world"转换为一个 &str 类型的引用，并用 Box包装起来，你想使用这个引用，需要解引用*s |
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done! 很棒的练习题，其中几个例子也帮助我们对于字符串和切片有了更深刻的了解 |
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done! |
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完成打卡 2022/07/06 |
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第8题的答案是无法通过编译的，因为s1 没被使用 |
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utf8_slice Example 不能执行也不能修改 |
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那个依赖的库没实际被引入，只能作为代码片段参考而无法运行。 |
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Cargo.toml 中添加 然后到项目根目录下 cargo run 就可以运行了 |
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2022.11.11 Done |
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utf8_slice 的 Example 不能正常编译： |
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Cargo.toml 中添加 然后到项目根目录下 cargo run 就可以运行了 |
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Done。连着做十几道题好累，昏昏沉沉快做睡着了。 |
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第10题直接猪脑过载 |
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1、第一题 主要说明正常无法使用 Q: // 修复错误，不要新增代码行
fn main() {
let s: str = "hello, world";
}A: // 修复错误，不要新增代码行
fn main() {
let s: &str = "hello, world";//str->&str
}2、第二题，两种解法 如果要使用 Q: // 使用至少两种方法来修复错误
fn main() {
let s: Box<str> = "hello, world".into();
greetings(s)
}
fn greetings(s: &str) {
println!("{}",s)
}A: // 第一种解法
fn main() {
let s: &str = "hello, world";//一开始就保证变量为&str
greetings(s)
}
fn greetings(s: &str) {
println!("{}",s)
}//第二种解法
fn main() {
let s: Box<str> = "hello, world".into();
greetings(&s)//可以将`Box<str>`转换为`&str`类型
}
fn greetings(s: &str) {
println!("{}",s)
}3、第三题，创建String类型 Q: fn main() {
let mut s = __;//填空
s.push_str("hello, world");
s.push('!');
assert_eq!(s, "hello, world!");
}A: fn main() {
let mut s = String::new();
s.push_str("hello, world");
s.push('!');
assert_eq!(s, "hello, world!");
}4、第四题，字符换的拼接问题 Q: // 修复所有错误，并且不要新增代码行
fn main() {
let s = String::from("hello");
s.push(',');
s.push(" world");
s += "!".to_string();
println!("{}", s)
}A: // 修复所有错误，并且不要新增代码行
fn main() {
let mut s = String::from("hello");//需要声明这个String的值可变
s.push(',');
s.push_str(" world");//拼接字符串需要用push_str()方法
s += "!";//拼接必须保证右边为'&str'类型
println!("{}", s)
}5、第五题， Q: // 填空
fn main() {
let s = String::from("I like dogs");
// 以下方法会重新分配一块内存空间，然后将修改后的字符串存在这里
let s1 = s.__("dogs", "cats");
assert_eq!(s1, "I like cats")
}A: // 填空
fn main() {
let s = String::from("I like dogs");
// 以下方法会重新分配一块内存空间，然后将修改后的字符串存在这里
let s1 = s.replace("dogs", "cats");
assert_eq!(s1, "I like cats")
}6、第六题 Q: // 修复所有错误，不要删除任何一行代码
fn main() {
let s1 = String::from("hello,");
let s2 = String::from("world!");
let s3 = s1 + s2;
assert_eq!(s3,"hello,world!");
println!("{}",s1);
}A: // 修复所有错误，不要删除任何一行代码
fn main() {
let s1 = String::from("hello,");
let s2 = String::from("world!");
let s3 = s1.clone() + &s2; //拼接必然是String+&str……，同时拼接后s1丧失所有权，所以这边要用深度拷贝clone来避免后续s1调用失败的情况
assert_eq!(s3,"hello,world!");
println!("{}",s1);
}7、第七题，两种方法将 Q: // 使用至少两种方法来修复错误
fn main() {
let s = "hello, world";
greetings(s)
}
fn greetings(s: String) {
println!("{}",s)
}A: // 使用至少两种方法来修复错误
fn main() {
let s = "hello, world".to_string();//第一种
greetings(s)
}
fn greetings(s: String) {
println!("{}",s)
}// 使用至少两种方法来修复错误
fn main() {
let s = String::from("hello, world");
greetings(s)
}
fn greetings(s: String) {
println!("{}",s)
}8、第八题， Q: // 使用两种方法来解决错误，不要新增代码行
fn main() {
let s = "hello, world".to_string();
let s1: &str = s;
}A: //第0种，一开始就不要让String出现（狗头）
fn main() {
let s = "hello, world";
let s1: &str = s;
}// 第一种:as_str
fn main() {
let s = "hello, world".to_string();
let s1: &str = s.as_str();
}//第二种，切片
fn main() {
let s = "hello, world".to_string();
let s1: &str = &s[..];
}//第三种，引用
fn main() {
let s = "hello, world".to_string();
let s1: &str = &s;
}9、第九题，字符串转义 Q: fn main() {
// 你可以使用转义的方式来输出想要的字符，这里我们使用十六进制的值，例如 \x73 会被转义成小写字母 's'
// 填空以输出 "I'm writing Rust"
let byte_escape = "I'm writing Ru\x73__!";
println!("What are you doing\x3F (\\x3F means ?) {}", byte_escape);
// 也可以使用 Unicode 形式的转义字符
let unicode_codepoint = "\u{211D}";
let character_name = "\"DOUBLE-STRUCK CAPITAL R\"";
println!("Unicode character {} (U+211D) is called {}",
unicode_codepoint, character_name );
// 还能使用 \ 来连接多行字符串
let long_string = "String literals
can span multiple lines.
The linebreak and indentation here \
can be escaped too!";
println!("{}", long_string);
}A: fn main() {
// 你可以使用转义的方式来输出想要的字符，这里我们使用十六进制的值，例如 \x73 会被转义成小写字母 's'
// 填空以输出 "I'm writing Rust"
let byte_escape = "I'm writing Ru\x73\x74!";
println!("What are you doing\x3F (\\x3F means ?) {}", byte_escape);
// 也可以使用 Unicode 形式的转义字符
let unicode_codepoint = "\u{211D}";
let character_name = "\"DOUBLE-STRUCK CAPITAL R\"";
println!("Unicode character {} (U+211D) is called {}",
unicode_codepoint, character_name );
// 还能使用 \ 来连接多行字符串
let long_string = "String literals
can span multiple lines.
The linebreak and indentation here \
can be escaped too!";
println!("{}", long_string);
}10、 Q: /* 填空并修复所有错误 */
fn main() {
let raw_str = r"Escapes don't work here: \x3F \u{211D}";
// 修改上面的行让代码工作
assert_eq!(raw_str, "Escapes don't work here: ? ℝ");
// 如果你希望在字符串中使用双引号，可以使用以下形式
let quotes = r#"And then I said: "There is no escape!""#;
println!("{}", quotes);
// 如果希望在字符串中使用 # 号，可以如下使用：
let delimiter = r###"A string with "# in it. And even "##!"###;
println!("{}", delimiter);
// 填空
let long_delimiter = __;
assert_eq!(long_delimiter, "Hello, \"##\"")
}A: /* 填空并修复所有错误 */
fn main() {
let raw_str = "Escapes don't work here: \x3F \u{211D}";
// 这边需要删除r使得字符码被识别
assert_eq!(raw_str, "Escapes don't work here: ? ℝ");
// 如果你希望在字符串中使用双引号，可以使用以下形式
let quotes = r#"And then I said: "There is no escape!""#;
println!("{}", quotes);
// 如果希望在字符串中使用 # 号，可以如下使用：
let delimiter = r###"A string with "# in it. And even "##!"###;
println!("{}", delimiter);
// 填空
let long_delimiter = "Hello, \"##\"";//在双引号之前加\转义
assert_eq!(long_delimiter, "Hello, \"##\"")
}11、第十一题，字符串索引 Q: fn main() {
let s1 = String::from("hi,中国");
let h = s1[0]; // 修改当前行来修复错误，提示: `h` 字符在 UTF-8 格式中只需要 1 个字节来表示
assert_eq!(h, "h");
let h1 = &s1[3..5];// 修改当前行来修复错误，提示: `中` 字符在 UTF-8 格式中需要 3 个字节来表示
assert_eq!(h1, "中");
}A: fn main() {
let s1 = String::from("hi,中国");
let h = &s1[0..1]; //切片大小为1
assert_eq!(h, "h");
let h1 = &s1[3..6];// 修改当前行来修复错误，提示: `中` 字符在 UTF-8 格式中需要 3 个字节来表示
assert_eq!(h1, "中");
}12、第十二题，操作UTF-8字符串 Q: fn main() {
// 填空，打印出 "你好，世界" 中的每一个字符
for c in "你好，世界".__ {
println!("{}", c)
}
}A: fn main() {
// 填空，打印出 "你好，世界" 中的每一个字符
for c in "你好，世界".chars() {
println!("{}", c)
}
}
//打印的结果是：
/*
你
好
，
世
界
*/如果是调用 |
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1、第一题 主要说明正常无法使用 Q: // 修复错误，不要新增代码行
fn main() {
let s: str = "hello, world";
}A: // 修复错误，不要新增代码行
fn main() {
let s: &str = "hello, world";//str->&str
}2、第二题，两种解法 如果要使用 Q: // 使用至少两种方法来修复错误
fn main() {
let s: Box<str> = "hello, world".into();
greetings(s)
}
fn greetings(s: &str) {
println!("{}",s)
}A: // 第一种解法
fn main() {
let s: &str = "hello, world";//一开始就保证变量为&str
greetings(s)
}
fn greetings(s: &str) {
println!("{}",s)
}//第二种解法
fn main() {
let s: Box<str> = "hello, world".into();
greetings(&s)//可以将`Box<str>`转换为`&str`类型
}
fn greetings(s: &str) {
println!("{}",s)
}3、第三题，创建String类型 Q: fn main() {
let mut s = __;//填空
s.push_str("hello, world");
s.push('!');
assert_eq!(s, "hello, world!");
}A: fn main() {
let mut s = String::new();
s.push_str("hello, world");
s.push('!');
assert_eq!(s, "hello, world!");
}4、第四题，字符换的拼接问题 Q: // 修复所有错误，并且不要新增代码行
fn main() {
let s = String::from("hello");
s.push(',');
s.push(" world");
s += "!".to_string();
println!("{}", s)
}A: // 修复所有错误，并且不要新增代码行
fn main() {
let mut s = String::from("hello");//需要声明这个String的值可变
s.push(',');
s.push_str(" world");//拼接字符串需要用push_str()方法
s += "!";//拼接必须保证右边为'&str'类型
println!("{}", s)
}5、第五题， Q: // 填空
fn main() {
let s = String::from("I like dogs");
// 以下方法会重新分配一块内存空间，然后将修改后的字符串存在这里
let s1 = s.__("dogs", "cats");
assert_eq!(s1, "I like cats")
}A: // 填空
fn main() {
let s = String::from("I like dogs");
// 以下方法会重新分配一块内存空间，然后将修改后的字符串存在这里
let s1 = s.replace("dogs", "cats");
assert_eq!(s1, "I like cats")
}6、第六题 Q: // 修复所有错误，不要删除任何一行代码
fn main() {
let s1 = String::from("hello,");
let s2 = String::from("world!");
let s3 = s1 + s2;
assert_eq!(s3,"hello,world!");
println!("{}",s1);
}A: // 修复所有错误，不要删除任何一行代码
fn main() {
let s1 = String::from("hello,");
let s2 = String::from("world!");
let s3 = s1.clone() + &s2; //拼接必然是String+&str……，同时拼接后s1丧失所有权，所以这边要用深度拷贝clone来避免后续s1调用失败的情况
assert_eq!(s3,"hello,world!");
println!("{}",s1);
}7、第七题，两种方法将 Q: // 使用至少两种方法来修复错误
fn main() {
let s = "hello, world";
greetings(s)
}
fn greetings(s: String) {
println!("{}",s)
}A: // 使用至少两种方法来修复错误
fn main() {
let s = "hello, world".to_string();//第一种
greetings(s)
}
fn greetings(s: String) {
println!("{}",s)
}// 使用至少两种方法来修复错误
fn main() {
let s = String::from("hello, world");
greetings(s)
}
fn greetings(s: String) {
println!("{}",s)
}8、第八题， Q: // 使用两种方法来解决错误，不要新增代码行
fn main() {
let s = "hello, world".to_string();
let s1: &str = s;
}A: //第0种，一开始就不要让String出现（狗头）
fn main() {
let s = "hello, world";
let s1: &str = s;
}// 第一种:as_str
fn main() {
let s = "hello, world".to_string();
let s1: &str = s.as_str();
}//第二种，切片
fn main() {
let s = "hello, world".to_string();
let s1: &str = &s[..];
}//第三种，引用
fn main() {
let s = "hello, world".to_string();
let s1: &str = &s;
}9、第九题，字符串转义 Q: fn main() {
// 你可以使用转义的方式来输出想要的字符，这里我们使用十六进制的值，例如 \x73 会被转义成小写字母 's'
// 填空以输出 "I'm writing Rust"
let byte_escape = "I'm writing Ru\x73__!";
println!("What are you doing\x3F (\\x3F means ?) {}", byte_escape);
// 也可以使用 Unicode 形式的转义字符
let unicode_codepoint = "\u{211D}";
let character_name = "\"DOUBLE-STRUCK CAPITAL R\"";
println!("Unicode character {} (U+211D) is called {}",
unicode_codepoint, character_name );
// 还能使用 \ 来连接多行字符串
let long_string = "String literals
can span multiple lines.
The linebreak and indentation here \
can be escaped too!";
println!("{}", long_string);
}A: fn main() {
// 你可以使用转义的方式来输出想要的字符，这里我们使用十六进制的值，例如 \x73 会被转义成小写字母 's'
// 填空以输出 "I'm writing Rust"
let byte_escape = "I'm writing Ru\x73\x74!";
println!("What are you doing\x3F (\\x3F means ?) {}", byte_escape);
// 也可以使用 Unicode 形式的转义字符
let unicode_codepoint = "\u{211D}";
let character_name = "\"DOUBLE-STRUCK CAPITAL R\"";
println!("Unicode character {} (U+211D) is called {}",
unicode_codepoint, character_name );
// 还能使用 \ 来连接多行字符串
let long_string = "String literals
can span multiple lines.
The linebreak and indentation here \
can be escaped too!";
println!("{}", long_string);
}10、 Q: /* 填空并修复所有错误 */
fn main() {
let raw_str = r"Escapes don't work here: \x3F \u{211D}";
// 修改上面的行让代码工作
assert_eq!(raw_str, "Escapes don't work here: ? ℝ");
// 如果你希望在字符串中使用双引号，可以使用以下形式
let quotes = r#"And then I said: "There is no escape!""#;
println!("{}", quotes);
// 如果希望在字符串中使用 # 号，可以如下使用：
let delimiter = r###"A string with "# in it. And even "##!"###;
println!("{}", delimiter);
// 填空
let long_delimiter = __;
assert_eq!(long_delimiter, "Hello, \"##\"")
}A: /* 填空并修复所有错误 */
fn main() {
let raw_str = "Escapes don't work here: \x3F \u{211D}";
// 这边需要删除r使得字符码被识别
assert_eq!(raw_str, "Escapes don't work here: ? ℝ");
// 如果你希望在字符串中使用双引号，可以使用以下形式
let quotes = r#"And then I said: "There is no escape!""#;
println!("{}", quotes);
// 如果希望在字符串中使用 # 号，可以如下使用：
let delimiter = r###"A string with "# in it. And even "##!"###;
println!("{}", delimiter);
// 填空
let long_delimiter = "Hello, \"##\"";//在双引号之前加\转义
assert_eq!(long_delimiter, "Hello, \"##\"")
}11、第十一题，字符串索引 Q: fn main() {
let s1 = String::from("hi,中国");
let h = s1[0]; // 修改当前行来修复错误，提示: `h` 字符在 UTF-8 格式中只需要 1 个字节来表示
assert_eq!(h, "h");
let h1 = &s1[3..5];// 修改当前行来修复错误，提示: `中` 字符在 UTF-8 格式中需要 3 个字节来表示
assert_eq!(h1, "中");
}A: fn main() {
let s1 = String::from("hi,中国");
let h = &s1[0..1]; //切片大小为1
assert_eq!(h, "h");
let h1 = &s1[3..6];// 修改当前行来修复错误，提示: `中` 字符在 UTF-8 格式中需要 3 个字节来表示
assert_eq!(h1, "中");
}12、第十二题，操作UTF-8字符串 Q: fn main() {
// 填空，打印出 "你好，世界" 中的每一个字符
for c in "你好，世界".__ {
println!("{}", c)
}
}A: fn main() {
// 填空，打印出 "你好，世界" 中的每一个字符
for c in "你好，世界".chars() {
println!("{}", c)
}
}
//打印的结果是：
/*
你
好
，
世
界
*/如果是调用 |
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done--2023/12/10 |
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第十题的填空 let long_delimiter = r###"Hello,\"##\""###;
println!("{}",long_delimiter);
assert_eq!(long_delimiter, "Hello,\"##\"");为什打印出来的字符串是 Hello,"##" ，后面的断言却不通过呢 |
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doneeeee////// >>>>> nice |
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感觉做课后作业的人不多啊。 |
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Done |
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Done |
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第三题我出现了一些错误，在Windows平台使用gnu工具链时出现了以下错误： error: could not compile 经过初步排查，似乎是由于s.push('!');引起的（因为我改成s.push_str('!');就可以成功运行了 |
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// 使用至少两种方法来修复错误 fn greetings(s: &str) { |
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mark finished |
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and others
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compound-types/string
Learning Rust By Practice, narrowing the gap between beginner and skilled-dev with challenging examples, exercises and projects.
https://zh.practice.rs/compound-types/string.html
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